// 指定最后一个元素的边框线条的高度
border-none($height)
    &:last-child
        &:after
            height $height

//产生 手机 1 像素的线条的混合
border-mix($color)
    position relative
    &:after
        display block
        position absolute
        bottom 0
        content ''
        width 100%
        height 1px
        background $color
        @media screen and (-webkit-device-pixel-ratio 2)
            transform scaleY(0.5)
        @media screen and (-webkit-device-pixel-ratio 3)
            transform scaleY(0.3333)
        @media screen and (-webkit-device-pixel-ratio 3.5)
            transform scaleY(0.2857)
        @media screen and (-webkit-device-pixel-ratio 2.6)
            transform scaleY(0.3846)
        @media screen and (-webkit-device-pixel-ratio 2.5)
            transform scaleY(0.4)

//用于使图片匹配手机与 css 像素与比的混合
background-img-mix($name)
        // background-image url('./img/'+$name+'@3x.png')
        @media screen and (-webkit-device-pixel-ratio 2)
            background-image url('./img/'+$name+'@2x.png')
        @media screen and (-webkit-device-pixel-ratio 3)
            background-image url('./img/'+$name+'@3x.png')
        @media screen and (-webkit-device-pixel-ratio 3.5)
            background-image url('./img/'+$name+'@3x.png') 
        @media screen and (-webkit-device-pixel-ratio 2.6) 
            background-image url('./img/'+$name+'@3x.png') !important
        @media screen and (-webkit-device-pixel-ratio 2.4) 
            background-image url('./img/'+$name+'@3x.png') !important
        @media screen and (-webkit-device-pixel-ratio 2.5)
            background-image url('./img/'+$name+'@3x.png')